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2.
Prague Med Rep ; 123(4): 250-257, 2022.
Article in English | MEDLINE | ID: covidwho-2145507

ABSTRACT

The SARS-CoV-2 viral load in a respiratory sample can be inversely quantified using the cycle threshold (Ct), defined as the number of amplification cycles required to detect the viral genome in a quantitative PCR assay using reverse transcriptase (RT-qPCR). It may be classified as high (Ct < 25), intermediate (25-30) and low (Ct > 30). We describe the clinical course of 3 patients with haematological neoplasms who contracted COVID-19. None of them had been vaccinated. Firstly, a 22-year-old male with a refractory acute lymphoblastic leukaemia experienced an oligosymptomatic COVID-19 and had a Ct of 23 with an ascending curve. Another male, aged 23, had recently begun treatment for a promyelocytic leukaemia. He had a subacute course with high oxygen requirements. His Ct dropped from 28, when he only experienced fever, to 14.8, during the most critical period and on the edge of ventilatory support. Viral clearance was documented 126 days after the beginning of the symptoms. Finally, a 60-year-old male had received rituximab as maintenance therapy for a follicular lymphoma 3 months before contracting COVID-19. He had a fulminant course and required mechanical ventilation a few days later. We highlight the association between the course of CoViD-19 and the Ct. Viral shedding was longer than in immunocompetent hosts.


Subject(s)
COVID-19 , Hematologic Neoplasms , Neoplasms , Humans , Male , Young Adult , Adult , Middle Aged , RNA, Viral/analysis , RNA, Viral/genetics , SARS-CoV-2 , Hematologic Neoplasms/complications
3.
PLoS One ; 17(11): e0278061, 2022.
Article in English | MEDLINE | ID: covidwho-2140683

ABSTRACT

Contaminated surfaces are one of the ways that coronavirus disease 2019 (COVID-19) may be transmitted. SARS-CoV-2 can be detected on environmental surfaces; however, few environmental sampling studies have been conducted in nonclinical settings. The objective of this study was to detect SARS-CoV-2 RNA on environmental surfaces in public areas in Las Vegas, Nevada. In total, 300 surface samples were collected from high-touch surfaces from high-congregate public locations and from a public health facility (PHF) that was visited by COVID-19 patients. Environmental samples were analyzed with quantitative reverse-transcriptase polymerase chain reaction (RT-qPCR) using SARS-CoV-2 specific primers and probes for three target genes. Results showed that 31 out of 300 (10.3%) surface samples tested positive for SARS-CoV-2, 24 at the PHF and 7 in high-congregate public locations. Concentrations ranged from 102 to 106 viral particles per 3 ml sample on a wide variety of materials. The data also showed that the N gene assay had greater sensitivity compared to the S and ORF gene assays. Besides frequently touched surfaces, SARS-CoV-2 was detected in restrooms, on floors and surfaces in contact with floors, as well as in a mop water sample. The results of this study describe the extent and distribution of environmental SARS-CoV-2 contamination in public areas in Las Vegas, Nevada. A method using the N gene PCR assay was developed for SARS-CoV-2 environmental monitoring in public areas. Environmental monitoring with this method can determine the specific sites of surface contamination in the community and may be beneficial for prevention of COVID-19 indirect transmission, and evaluation and improvement of infection control practices in public areas, public health facilities, universities, and businesses.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , RNA, Viral/genetics , RNA, Viral/analysis , COVID-19/epidemiology , Specimen Handling , DNA Primers
4.
PLoS One ; 17(11): e0277881, 2022.
Article in English | MEDLINE | ID: covidwho-2140668

ABSTRACT

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) causes the global COVID-19 pandemic. Limited studies have been performed on various types of disinfectants utilized to control the spread of this highly contagious virus. This study aimed to investigate the inactivation of SARS-CoV-2 using compressed sodium chloride (CSC) surface. A real-time reverse transcriptase quantitative PCR (RT-qPCR) assay was used to evaluate the effectiveness of CSC on the disintegration of viral RNA in a time dependent manner. The effects of CSC on viral infectivity were determined using a TCID50 assay of a surrogate virus, hCoV-229E, in MRC-5 cell culture. The results demonstrated that CSC achieved a 2 to 3- log10 reduction of viral genomic RNA for a laboratory strain of hCoV-229E, and clinical samples of hCoV-229E and hCoV-OC43. A 3 to 4-log10 reduction was observed for SARS-CoV-2 (RdRp and E gene) suggesting that a CSC surface could effectively disintegrate the SARS-CoV-2 RNA genome. CSC was observed to have a 6 log10 inactivation of infectious hCoV-229E using cell culture after 5 minutes of exposure compared to the control, indicating good disinfection efficacy of a CSC surface against virus.


Subject(s)
COVID-19 , Coronavirus 229E, Human , Humans , SARS-CoV-2 , RNA, Viral/genetics , RNA, Viral/analysis , Sodium Chloride/pharmacology , Pandemics
5.
Clin Lab Med ; 42(2): 237-248, 2022 06.
Article in English | MEDLINE | ID: covidwho-2130431

ABSTRACT

Reverse transcription-polymerase chain reaction (RT-PCR) tests for severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the cause of coronavirus disease 2019 (COVID-19), are approved for qualitative use. The cycle threshold (Ct) value reflects the concentration of viral RNA in the sample, with lower Ct values indicating higher levels of RNA. Caregivers may wish to use the Ct value to determine the progression of infection, how severe the infection will be, and whether the patient can transmit the virus. Variability of Ct values and the data supporting these uses should be considered when deciding whether and how to use Ct values in clinical care.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19/diagnosis , Humans , RNA, Viral/analysis , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction , Reverse Transcription , SARS-CoV-2/genetics
6.
Anal Chim Acta ; 1234: 340533, 2022 Nov 22.
Article in English | MEDLINE | ID: covidwho-2129675

ABSTRACT

The emerging pandemic of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) critically challenges early and accurate virus diagnoses. However, the current gold standard for SARS-CoV-2 detection, reverse transcription-quantitative polymerase chain reaction (RT-qPCR), has reportedly failed to detect low-viral loads. One compound, graphene oxide (GO), which adsorbs single-stranded DNA (ssDNA), has been widely applied in molecular pathogen detection. This study presents a highly sensitive GO-multiplex qPCR method for simultaneous detection of two SARS-CoV-2 genes (RdRP and E) and one reference gene (RNase P). In a GO-multiplex qPCR system, GO pre-absorbs each forward primer to form specific GO-forward primer composites before entering the amplification system. Target gene amplification is confined within the primer-enriched composites, thus, improving the sensitivity of the assay. Compared to conventional multiplex qPCR, GO-multiplex qPCR reduces the limit of detection by 10-fold to 10 copies/reaction. Hence, the GO-multiplex qPCR assay can be effectively used for SARS-CoV-2 detection.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , COVID-19 Testing , Clinical Laboratory Techniques/methods , COVID-19/diagnosis , RNA, Viral/genetics , RNA, Viral/analysis , Sensitivity and Specificity
7.
Klin Lab Diagn ; 67(11): 663-667, 2022 Nov 14.
Article in English | MEDLINE | ID: covidwho-2146780

ABSTRACT

The coronavirus infection continues to spread around the world. In this regard, the purpose of this work was: to develop a set of reagents for the qualitative detection of SARS-CoV-2 virus RNA. The set was developed by CJSC «Ecolab¼, 20 positive samples were used to develop the kit. The research method consisted of several stages: isolation of SARS-CoV-2 RNA, RNA reverse transcription reaction and PCR amplification of cDNA with simultaneous detection of the result in real time. The main characteristics of the kit: analytical sensitivity - 100%, specificity - 100%, accuracy - 100%. Thus, our method for diagnosing a new coronavirus infection based on real-time RT-PCR makes it possible to qualitatively and quickly detect betacoronavirus RNA in clinical material from patients and healthy individuals with suspected coronavirus infection and other symptoms of SARS.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/genetics , RNA, Viral/analysis , Indicators and Reagents , Sensitivity and Specificity , COVID-19/diagnosis , Real-Time Polymerase Chain Reaction
8.
Sensors (Basel) ; 22(22)2022 Nov 09.
Article in English | MEDLINE | ID: covidwho-2110221

ABSTRACT

Real-time Polymerase Chain Reaction (RT-PCR), a molecular diagnostic technology, is spotlighted as one of the quickest and fastest diagnostic methods for the actual coronavirus (SARS-CoV-2). However, the fluorescent label-based technology of the RT-PCR technique requires expensive equipment and a sample pretreatment process for analysis. Therefore, this paper proposes a biochip based on Electrochemical Impedance Spectroscopy (EIS). In this paper, it was possible to see the change according to the concentration by measuring the impedance with a chip made of two electrodes with different shapes of sample DNA.


Subject(s)
COVID-19 , Gene Amplification , Humans , RNA, Viral/analysis , SARS-CoV-2/genetics , COVID-19/diagnosis , Electrodes
9.
BMC Genomics ; 23(1): 755, 2022 Nov 17.
Article in English | MEDLINE | ID: covidwho-2116898

ABSTRACT

BACKGROUND: Since inception of the COVID-19 pandemic, early detection and isolation of positive cases is one of the key strategies to restrict disease transmission. Real time reverse transcription polymerase chain reaction (qRTPCR) has been the mainstay of diagnosis. Most of the qRTPCR kits were designed against the target genes of original strain of SARS-CoV-2. However, with the emergence of variant strains of SARS-CoV-2, sensitivity of the qRTPCR assays has reportedly reduced. In view of this, it is critical to continuously monitor the performance of the qRTPCR kits in the backdrop of variant strains of SARS-CoV-2. Real world monitoring of assay performance is challenging. Therefore, we developed a two-step in-silico screening process for evaluating the performance of various qRTPCR kits used in India. RESULTS: We analysed 73 qRT-PCR kits marketed in India, against the two SARS-CoV-2 VoCs. Sequences of both Delta (B.1.617.2) and Omicron (B.1.1.529) VoCs submitted to GISAID within a specific timeframe were downloaded, clustered to identify unique sequences and aligned with primer and probe sequences. Results were analysed following a two-step screening process. Out of 73 kits analysed, seven were unsatisfactory for detection of both Delta and Omicron VoCs, 10 were unsatisfactory for Delta VoC whereas 2 were unsatisfactory for only Omicron VoC. CONCLUSION: Overall, we have developed a useful screening process for evaluating the performance of qRTPCR assays against Delta and Omicron VoCs of SARS-CoV-2 which can be used for detecting SARS-CoV-2 VoCs that may emerge in future and can also be redeployed for other evolving pathogens of public health importance.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , Pandemics , RNA, Viral/genetics , RNA, Viral/analysis , Sensitivity and Specificity , COVID-19/diagnosis , COVID-19/epidemiology
10.
Clin Infect Dis ; 75(10): 1698-1705, 2022 Nov 14.
Article in English | MEDLINE | ID: covidwho-2116480

ABSTRACT

The novel coronavirus pandemic incited unprecedented demand for assays that detect viral nucleic acids, viral proteins, and corresponding antibodies. The 320 molecular diagnostics in receipt of US Food and Drug Administration emergency use authorization mainly focus on viral detection; however, no currently approved test can be used to infer infectiousness, that is, the presence of replicable virus. As the number of tests conducted increased, persistent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA positivity by reverse-transcription polymerase chain reaction (RT-PCR) in some individuals led to concerns over quarantine guidelines. To this end, we attempted to design an assay that reduces the frequency of positive test results from individuals who do not shed culturable virus. We describe multiplex quantitative RT-PCR assays that detect genomic RNA (gRNA) and subgenomic RNA (sgRNA) species of SARS-CoV-2, including spike, nucleocapsid, membrane, envelope, and ORF8. Viral RNA abundances calculated from these assays were compared with antigen presence, self-reported symptoms, and culture outcome (virus isolation) using samples from a 14-day longitudinal household transmission study. By characterizing the clinical and molecular dynamics of infection, we show that sgRNA detection has higher predictive value for culture outcome compared to detection of gRNA alone. Our findings suggest that sgRNA presence correlates with active infection and may help identify individuals shedding culturable virus.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , RNA, Viral/genetics , RNA, Viral/analysis , Self Report , Longitudinal Studies , RNA, Guide , COVID-19/diagnosis
11.
Viruses ; 14(11)2022 Nov 21.
Article in English | MEDLINE | ID: covidwho-2116086

ABSTRACT

Background: The transmissible capacity and toxicity of SARS-CoV-2 variants are continually changing. We report here the follow-up study of hospitalized COVID-19 patients from 2020 to 2022. It is known that the PCR diagnosis for hospitalized patients sometimes causes confusion because of the incompatibility between their diagnosis and symptoms. We applied our sugar chain-immobilized gold-nanoparticles for the extraction and partial purification of RNA from specimens for quantitative RT-PCR assay and evaluated whether the results correlate with patients' symptoms. Methods and Results: Saliva specimens were taken from hospitalized patients with mild or moderate symptoms every early morning. At the time of RT-PCR diagnosis, two methods for the extraction and partial purification of RNA from the specimen were performed: a commonly used Boom (Qiagen) method and our original sugar chain-immobilized gold nanoparticle (SGNP) method. For symptoms, body temperature and oxygen saturation (SpO2) of patients were monitored every 4 h. Conclusions: It was clear that patients infected with the Delta variant needed more time to recover than those with the Omicron variant, and that the SGNP method showed more realistic correlation with the symptoms of patients compared with the common Qiagen method.


Subject(s)
COVID-19 , Metal Nanoparticles , Humans , Reverse Transcriptase Polymerase Chain Reaction , Gold , SARS-CoV-2/genetics , Sugars , Follow-Up Studies , COVID-19/diagnosis , RNA, Viral/genetics , RNA, Viral/analysis , Sensitivity and Specificity , Carbohydrates
12.
MEDICC Rev ; 24(2): 7-14, 2022 May 16.
Article in English | MEDLINE | ID: covidwho-2115047

ABSTRACT

INTRODUCTION: COVID-19 sequelae, or the short-, medium-, and long-term manifestations of the disease are under continuous study. There are currently few reports on the evolution of hematological variables following a demonstrated absence of SARS-CoV-2 after infection. OBJECTIVE: Identify hematological alterations in Cuban adults recovered from SARS-CoV-2 infection, and their relation with disease severity. METHODS: We selected 348 persons recovered from COVID-19 residing in Havana, Cuba with an RT-PCR study negative for SARS-CoV-2 performed two weeks after hospital discharge; a structured survey was administered to obtain clinical-epidemiological data. Three groups were established according to COVID-19 clinical criteria: asymptomatic, mild/moderately symptomatic, and severely symptomatic, which, in turn, were divided according to hospital discharge date and blood sample collection date. We performed hemograms with differential leukocyte counts and compared results among groups. We then measured the associations between hematological variables, personal medical history, and relevant lifestyle habits (smoking). RESULTS: All hematological variables were within normal reference limits, although men from the group of severely ill patients had increased total leukocytes, neutrophils and lymphocytes, and decreased hemoglobin and eosinophils, which was also evident in those with a recovery time of 31-90 days. CONCLUSIONS: The relation between hematological variables and degree of clinical severity offers evidence as to persistence of systemic alterations (possibly inflammatory) associated with viral infection. Their identification and characterization can facilitate personalized patient followup and rehabilitation.


Subject(s)
COVID-19 , Adult , Cuba/epidemiology , Humans , Male , RNA, Viral/analysis , SARS-CoV-2 , Severity of Illness Index
13.
PLoS One ; 17(11): e0277367, 2022.
Article in English | MEDLINE | ID: covidwho-2109332

ABSTRACT

The use of a non-invasive fluorescence in situ hybridization (FISH)-based method on saliva for the detection of SARS-CoV-2 is evaluated in a proof-of-concept study and thereafter utilized in an outpatient setting with the Biotrack-MED® analyzer. For a proof-of-concept study, saliva samples were obtained from 28 persons with mild or moderate COVID-19-related symptoms who were tested RT-PCR positive or negative for SARS-CoV-2. In an outpatient setting, 972 individual saliva samples were utilized. All saliva samples were FISHed with a Cy3-labeled SARS-CoV-2-specific DNA probe and were analyzed manually by fluorescence microscopy (proof-of-concept) or with the SARS-CoV-2 application of the Biotrack-MED® analyzer, a semi-autonomous multi-sample filter cytometer. The proof-of-concept study showed a sensitivity of 96.0% and a specificity of 98.5% and is therefore comparable to the RT-PCR analysis of nasopharyngeal swabs. The outpatient setting showed a sensitivity of 90.9% and a specificity of 94.5% and seems therefore a valid assay for the detection of SARS-CoV-2 in individuals that are healthy, mild or moderate symptomatic. In conclusion, the method evaluated in this study, the FISH-based SARS-CoV-2 application of the Biotrack-MED® analyzer, is a sensitive and reliable assay for the detection of SARS-CoV-2 in the general population.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , SARS-CoV-2/genetics , Saliva/chemistry , COVID-19/diagnosis , In Situ Hybridization, Fluorescence , RNA, Viral/genetics , RNA, Viral/analysis , Nasopharynx , Specimen Handling/methods
14.
PLoS One ; 17(11): e0277301, 2022.
Article in English | MEDLINE | ID: covidwho-2109330

ABSTRACT

PURPOSE: To assess hospitalized COVID-19 inpatients for the prevalence of retinopathy and tear film SARS-CoV-2 RNA, and associated risk factors for their detection. METHODS: Hospitalized COVID-19 patients underwent dilated ophthalmic examination and fundus photography. Conjunctival swabs were assessed for SARS-CoV-2 RT-PCR via a triple target assay. We assessed the relationships of retinopathy with clinical outcomes, systemic risk factors and laboratory data. RESULTS: The median age was 59.5 years and 29 (48%) were female. Retinopathy associated with COVID-19 was observed in 12 of 60 patients (20%). The median age of patients with COVID-19 retinopathy was 51.5 compared to 62.5 years in individuals without retinopathy (p = 0.01). Median BMI was 34.3 in patients with retinopathy versus 30.9 in those without retinopathy (p = 0.04). Fifteen of 60 patients (25%) tested SARS-CoV-2 RNA-positive in their tear film without a relationship with timing of illness and hospitalization. The N2 gene was particularly sensitive with 18 of 19 eyes (94.7%) showing N2-positivity, including 2 patients with alpha variant-positivity (B.1.1.7). CONCLUSION: Retinopathy was observed in 20% of patients hospitalized for COVID-19. Patients with retinopathy were more likely to be younger and have higher BMI than hospitalized patients without retinopathy. Tear film SARS-CoV-2 RNA was detected in 25% of patients. The relationship of obesity and age with retinopathy requires further investigation.


Subject(s)
COVID-19 , Retinal Diseases , Humans , Female , Middle Aged , Male , COVID-19/diagnosis , SARS-CoV-2/genetics , RNA, Viral/genetics , RNA, Viral/analysis , Reverse Transcriptase Polymerase Chain Reaction , Risk Factors
15.
IEEE Trans Biomed Eng ; 69(8): 2557-2568, 2022 08.
Article in English | MEDLINE | ID: covidwho-2107854

ABSTRACT

OBJECTIVE: The m6A modification is the most common ribonucleic acid (RNA) modification, playing a role in prompting the virus's gene mutation and protein structure changes in the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Nanopore single-molecule direct RNA sequencing (DRS) provides data support for RNA modification detection, which can preserve the potential m6A signature compared to second-generation sequencing. However, due to insufficient DRS data, there is a lack of methods to find m6A RNA modifications in DRS. Our purpose is to identify m6A modifications in DRS precisely. METHODS: We present a methodology for identifying m6A modifications that incorporated mapping and extracted features from DRS data. To detect m6A modifications, we introduce an ensemble method called mixed-weight neural bagging (MWNB), trained with 5-base RNA synthetic DRS containing modified and unmodified m6A. RESULTS: Our MWNB model achieved the highest classification accuracy of 97.85% and AUC of 0.9968. Additionally, we applied the MWNB model to the COVID-19 dataset; the experiment results reveal a strong association with biomedical experiments. CONCLUSION: Our strategy enables the prediction of m6A modifications using DRS data and completes the identification of m6A modifications on the SARS-CoV-2. SIGNIFICANCE: The Corona Virus Disease 2019 (COVID-19) outbreak has significantly influence, caused by the SARS-CoV-2. An RNA modification called m6A is connected with viral infections. The appearance of m6A modifications related to several essential proteins affects proteins' structure and function. Therefore, finding the location and number of m6A RNA modifications is crucial for subsequent analysis of the protein expression profile.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , RNA, Viral/analysis , RNA, Viral/genetics , SARS-CoV-2/genetics , Sequence Analysis, RNA
16.
Nature ; 611(7936): 570-577, 2022 11.
Article in English | MEDLINE | ID: covidwho-2106425

ABSTRACT

Expanding our global testing capacity is critical to preventing and containing pandemics1-9. Accordingly, accessible and adaptable automated platforms that in decentralized settings perform nucleic acid amplification tests resource-efficiently are required10-14. Pooled testing can be extremely efficient if the pooling strategy is based on local viral prevalence15-20; however, it requires automation, small sample volume handling and feedback not available in current bulky, capital-intensive liquid handling technologies21-29. Here we use a swarm of millimetre-sized magnets as mobile robotic agents ('ferrobots') for precise and robust handling of magnetized sample droplets and high-fidelity delivery of flexible workflows based on nucleic acid amplification tests to overcome these limitations. Within a palm-sized printed circuit board-based programmable platform, we demonstrated the myriad of laboratory-equivalent operations involved in pooled testing. These operations were guided by an introduced square matrix pooled testing algorithm to identify the samples from infected patients, while maximizing the testing efficiency. We applied this automated technology for the loop-mediated isothermal amplification and detection of the SARS-CoV-2 virus in clinical samples, in which the test results completely matched those obtained off-chip. This technology is easily manufacturable and distributable, and its adoption for viral testing could lead to a 10-300-fold reduction in reagent costs (depending on the viral prevalence) and three orders of magnitude reduction in instrumentation cost. Therefore, it is a promising solution to expand our testing capacity for pandemic preparedness and to reimagine the automated clinical laboratory of the future.


Subject(s)
Automation , COVID-19 Testing , Magnets , Molecular Diagnostic Techniques , Nucleic Acid Amplification Techniques , Robotics , SARS-CoV-2 , Humans , COVID-19/diagnosis , COVID-19/virology , COVID-19 Testing/methods , Molecular Diagnostic Techniques/economics , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/economics , Nucleic Acid Amplification Techniques/methods , Pandemics/prevention & control , RNA, Viral/analysis , RNA, Viral/genetics , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Sensitivity and Specificity , Algorithms , Automation/economics , Automation/methods , Robotics/methods , Indicators and Reagents/economics
17.
Int J Infect Dis ; 124: 41-44, 2022 Nov.
Article in English | MEDLINE | ID: covidwho-2105070

ABSTRACT

Despite the high number of SARS-CoV-2 infections, only a few cases of dual infection have been reported. Here, we describe a case of COVID-19 caused simultaneously by Delta and Omicron variants in an immunocompetent individual during the early emergence of Omicron variant. A 73-year-old man was hospitalized with suspected acute coronary syndrome and a positive test result for SARS-CoV-2 RNA was received during routine testing at the hospital. He experienced mild symptoms of COVID-19 and was discharged on the ninth day. We sequenced the SARS-CoV-2 whole genome from the sample obtained on admission. The viral sequence was classified as PANGO lineage B.1.1.10 by the Galaxy pipeline; however, on detailed manual analysis, we identified the presence of both Delta and Omicron variants. After excluding the possibilities of a recombinant virus or contamination in the sample, we confirmed the presence of dual infection in this patient. We highlight that dual infections with SARS-CoV-2 may be more common than expected but are difficult to detect during the waves of one dominant variant.


Subject(s)
COVID-19 , Male , Humans , Aged , COVID-19/diagnosis , RNA, Viral/genetics , RNA, Viral/analysis , SARS-CoV-2
18.
Viruses ; 14(11)2022 Oct 31.
Article in English | MEDLINE | ID: covidwho-2099853

ABSTRACT

The Omicron variant of SARS-CoV-2 spreads more easily than earlier variants, possibly as a result of a higher viral load in the upper respiratory tract and oral cavity. Hence, we investigated whether the Omicron variant generates a higher viral load than that of the Delta variant in saliva and nasopharynx. Both specimens were collected from 52 Omicron and 17 Delta cases at two time points one week apart and analyzed by qRT-PCR. Viral load was measured as 10 log RNA genome copies per 1000 human cells according to the WHO reference standard. We found that Omicron cases carried a higher viral load and had more sustained viral shedding compared to the Delta cases, especially in the nasopharynx.


Subject(s)
COVID-19 , Saliva , Humans , Nasopharynx/virology , RNA, Viral/genetics , RNA, Viral/analysis , Saliva/virology , SARS-CoV-2/genetics , Viral Load
19.
Anal Biochem ; 659: 114960, 2022 Dec 15.
Article in English | MEDLINE | ID: covidwho-2085839

ABSTRACT

COVID-19 pandemic highlighted the demand for the fast and reliable detection of viral RNA. Although various methods for RNA amplification and detection have been proposed, some limitations, including those caused by reverse transcription (RT), need to be overcome. Here, we report on the direct detection of specific RNA by conventional polymerase chain reaction (PCR) requiring no prior RT step. It was found that Hemo KlenTaq (HKTaq), which is posed as DNA-dependent DNA polymerase, possesses reverse transcriptase activity and provides reproducible amplification of RNA targets with an efficiency comparable to common RT-PCR. Using nasopharyngeal swab extracts from COVID-19-positive patients, the high reliability of SARS-CoV-2 detection based on HKTaq was demonstrated. The most accurate detection of specific targets are provided by nearby primers, which allow to determine RNA in solutions affected to multiple freeze-thaw cycles. HKTaq can be used for elaboration of simplified amplification techniques intended for the analysis of any specific RNA and requiring only one DNA polymerase.


Subject(s)
COVID-19 , RNA, Viral , Humans , Clinical Laboratory Techniques/methods , COVID-19 Testing , Nucleic Acid Amplification Techniques/methods , Pandemics , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction , RNA, Viral/genetics , RNA, Viral/analysis , RNA-Directed DNA Polymerase/genetics , SARS-CoV-2/genetics , Sensitivity and Specificity , Taq Polymerase/metabolism
20.
Viruses ; 14(11)2022 Oct 22.
Article in English | MEDLINE | ID: covidwho-2082026

ABSTRACT

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is responsible for the global epidemic of Coronavirus Disease 2019 (COVID-19), with a significant impact on the global economy and human safety. Reverse transcription-quantitative polymerase chain reaction (RT-PCR) is the gold standard for detecting SARS-CoV-2, but because the virus's genome is prone to mutations, the effectiveness of vaccines and the sensitivity of detection methods are declining. Variants of concern (VOCs) include Alpha, Beta, Gamma, Delta, and Omicron, which are able to evade recognition by host immune mechanisms leading to increased transmissibility, morbidity, and mortality of COVID-19. A range of research has been reported on detection techniques for VOCs, which is beneficial to prevent the rapid spread of the epidemic, improve the effectiveness of public health and social measures, and reduce the harm to human health and safety. However, a meaningful translation of this that reduces the burden of disease, and delivers a clear and cohesive message to guide daily clinical practice, remains preliminary. Herein, we summarize the capabilities of various nucleic acid and protein-based detection methods developed for VOCs in identifying and differentiating current VOCs and compare the advantages and disadvantages of each method, providing a basis for the rapid detection of VOCs strains and their future variants and the adoption of corresponding preventive and control measures.


Subject(s)
COVID-19 , Epidemics , Humans , SARS-CoV-2/genetics , RNA, Viral/genetics , RNA, Viral/analysis , COVID-19/diagnosis , COVID-19/prevention & control
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